Since the discovery of biologically active metabolites of vitamin D there has been much interest in the preparation of structural analogs of these metabolites, because such compounds may represent useful therapeutic agents for the treatment of diseases resulting from calcium metabolism disorders. A variety of vitamin D-like compounds have been synthesized. See, for example, U.S. Pat. Nos. 3,741,996 directed to 1.alpha.-hydroxycholecalciferol; 3,907,843 directed to 1.alpha.-hydroxyergocalciferol; 3,786,062 directed to 22-dehydro-25-hydroxycholecalciferol; 4,069,321 directed to the preparation of various side chain-fluorinated vitamin D.sub.3 derivatives and side chain-fluorinated dihydrotachysterol analogs; 4,201,881 directed to 24,24-difluoro-1.alpha.,25-dihydroxycholecalciferol and 4,196,133 directed to 24,24-difluoro-25-hydroxycholecalciferol. Other metabolic alternatives are believed to be responsible for the metabolism and ultimate elimination of vitamin D compounds from the body, with the generally accepted recognition that 1.alpha.,25-dihydroxycholecalciferol (U.S. Pat. No. 3,697,559) is the circulating hormonal form of vitamin D.